1. Field of the Invention
The present invention relates to a dicing apparatus for a gallium arsenide wafer and a method thereof, particularly to a laser dicing apparatus for a gallium arsenide wafer and a method thereof.
2. Description of the Related Art
Gallium arsenide is a group III-V compound semiconductor. Gallium arsenide is a dark-gray solid and has a melting point of 1238° C.; it is stable in the air and not corroded by non-oxidizing acid at the temperature below 600° C. Gallium arsenide has a high electronic mobility, a low dielectric constant and a special energy-band structure, and can be used as a material for epitaxial growth.
As gallium arsenide has superior optoelectronic properties and a higher speed, it is usually used as optoelectronic elements, high-frequency communication elements and microwave communication elements, e.g. used in WLAN (Wireless Local Area Network), WLL(Wireless Local Loop), optical fiber communication, satellite communication, LMDS (Local Multipoint Distribution System), VSAT (Very Small Aperture Terminal), etc. Although a gallium arsenide chip functions better than a silicon chip, it had been only used in some military equipments, satellites or supercomputers because of its high cost, high signal noise ratio, and difficulties in packaging. It is until the emergence of wireless communication market that gallium arsenide was not extensively used. As the radio-frequency elements used for transmitting signals need chips of high working frequency, low energy consumption and low noise, gallium arsenide, which has a high switching speed and a high signal noise ratio, is naturally the best candidate thereof. However, gallium arsenide has higher cost, and its fabrication equipments are different from those used in general silicon processes.
Owing to its special electronic, physical, and optical characteristics, gallium arsenide is used as semiconductors or optoelectronic materials. Gallium arsenide is hard to machine because of its hardness and brittleness. However, cutting a gallium arsenide wafer into discrete chips is an indispensable procedure for a chip fabrication process. High-hardness gallium arsenide wafers must be cut with a high-hardness tool, which raises the cost. Besides, cutting high-hardness gallium arsenide is very time-consuming.
Accordingly, the present invention proposes a laser dicing apparatus for a gallium arsenide wafer and a method thereof in order to overcome the abovementioned problems.